A Synthetic Reverse Model Based on AIS and the Application - Advances in Computational Science and Engineering - page 253

In Figure 4,

| AC | is the distance from point P to the "abnormal plane".
| BD | is the distance from point Q to the "abnormal plane ";

| UV | is the threshold.

∵ | AC | <| UV |, and | BD | <| UV |;

∴ P and Q are abnormal.

Let fp (x) is the abnormal probability function of x ,

then fp (P) = | UV | - | AC | and fp (Q) = | UV | - | BD | represent the abnor-
mal probability of P and Q. And then,

∵ | AC | <| BD |,

∴ fp (P) > fp (Q) .

That is to say the abnormal probability of point P is higher than that of Q.

z

P

o

x

E

A

y

Q

F

B

Fig. 5. The simple distance model of behavior vector to normal plane

While in figure 5,

| AE | is the distance from point P to the "normal plane";

| BF | is the distance from point Q to "normal plane";
In the same way, fp (P) = | AE |, fp (Q) = | BF |. And then,